feat(extensions/web): add structuredClone function (#11572)

Co-authored-by: Luca Casonato <hello@lcas.dev>

1 files changed, 19 insertions, 0 deletions

diff --git a/cli/tests/unit/structured_clone_test.ts b/cli/tests/unit/structured_clone_test.ts
new file mode 100644
index 000000000..f25276165
--- /dev/null
+++ b/cli/tests/unit/structured_clone_test.ts
@@ -0,0 +1,19 @@
+import { assert, assertEquals } from "./test_util.ts";
+
+// Basic tests for the structured clone algorithm. Mainly tests TypeScript
+// typings. Actual functionality is tested in WPT.
+
+Deno.test("self.structuredClone", async () => {
+  const arrayOriginal = ["hello world"];
+  const channelOriginal = new MessageChannel();
+  const [arrayCloned, portTransferred] = self
+    .structuredClone([arrayOriginal, channelOriginal.port2], {
+      transfer: [channelOriginal.port2],
+    });
+  assert(arrayOriginal !== arrayCloned); // not the same identity
+  assertEquals(arrayCloned, arrayOriginal); // but same value
+  channelOriginal.port1.postMessage("1");
+  await new Promise((resolve) => portTransferred.onmessage = () => resolve(1));
+  channelOriginal.port1.close();
+  portTransferred.close();
+});